Complex Waveform Design Technologies For Radar System

Radar waveform has a key impact on radar performance,such as range resolution,Doppler sensitivity,low interception performance,clutter suppression,etc.With the development of digital array technology,MIMO radar system is gradually mature.This thesis is divided into two parts,which mainly studies the waveform design of traditional and new MIMO radar.For traditional radar,this thesis analyzed three common pulse compression waveforms,namely LFM,NLFM and phase coding,summarizes their time-frequency domain characteristics,pulse compression and ambiguity function performance through simulation experiments,and compares their advantages,disadvantages and applicable environment;Under the definition of generalized waveform,the transmitting period of radar pulse is also the content of waveform design.Aiming at the working mode of multiple groups of stagger pulses,this thesis proposed a method to optimize the stagger period through genetic algorithm and then optimize the frequency response of MTI filter.Based on the study of MIMO radar signal processing,this thesis summarized the performance index of MIMO waveform,and carries out the research on MIMO radar waveform.MIMO radar is divided into orthogonal waveform and partial correlation waveform according to the correlation between waveforms.On the one hand,this thesis studied the orthogonal waveform design of MIMO radar,and introduces the orthogonal waveform design based on phase coding and LFM signal;In this article,the orthogonal condition of NLFM signal is analyzed,and the orthogonal waveform design of NLFM signal by optimizing phase and frequency modulation factor is proposed.Its energy coverage is approximately omnidirectional and the pulse comprehensive performance is good.Finally,the energy coverage and Doppler tolerance of the above three waveforms are compared through simulation analysis.On the other hand,the partial correlation waveform design is studied,and the partial correlation waveform design based on phase coding,LFM with traditional and subarray methods are introduced;Combined with the idea of subarray and the orthogonality condition of NLFM signal,this thesis proposed the design of NLFM partial correlation waveform with subarray orthogonality.Finally,a partial correlation MIMO radar working mode based on mechanical scanning is proposed,and its advantages over conventional radar working mode are verified by simulation.